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Userspace runtime loader support for sub-library c18n #2267

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Userspace runtime loader support for sub-library c18n #2267

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a0b392e
rtld: Remove code to track start and end offsets of text and rodata
bsdjhb Oct 30, 2024
e91535e
rtld: Support multiple PT_GNU_RELRO program headers
bsdjhb Dec 6, 2024
7d6a2fd
rtld: Support multiple PLTs
bsdjhb Oct 28, 2024
716960b
elf: Add definition of PT_CHERI_BOUNDS program header type
bsdjhb Nov 12, 2024
1a3a972
elftoolchain: Add support for PT_CHERI_BOUNDS
bsdjhb Nov 12, 2024
706b550
rtld: Support narrower PCC bounds via PT_CHERI_BOUNDS
bsdjhb Nov 13, 2024
a10092d
fixup! rtld: Support narrower PCC bounds via PT_CHERI_BOUNDS
bsdjhb Jan 7, 2025
a0e96d5
rtld: Require PT_CHERI_BOUNDS to be exact
bsdjhb Nov 20, 2024
f6c3abd
elf: Add definitions for PT_COMPARTMENT and DT_C18NSTRTAB*
bsdjhb Dec 5, 2024
d607049
elftoolchain: Add support for PT_COMPARTMENT and DT_C18NSTRTAB*
bsdjhb Dec 5, 2024
c6bda98
rtld: Add compartments for sub-object compartments described by PT_CO…
bsdjhb Dec 6, 2024
51db786
rtld_c18n: Fix copy/paste typo in _rtld_safebox_code error messages
bsdjhb Dec 9, 2024
f179912
rtld: Use compartment IDs from sub-object compartments for policy enf…
bsdjhb Dec 9, 2024
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86 changes: 53 additions & 33 deletions libexec/rtld-elf/aarch64/reloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -120,23 +120,23 @@ arch_digest_note(struct Struct_Obj_Entry *obj __unused, const Elf_Note *note)
}

void
init_pltgot(Obj_Entry *obj)
init_pltgot(Plt_Entry *plt)
{

if (obj->pltgot != NULL) {
if (plt->pltgot != NULL) {
#ifdef CHERI_LIB_C18N
if (C18N_ENABLED)
obj->pltgot[1] = (uintptr_t)cheri_seal(obj,
plt->pltgot[1] = (uintptr_t)cheri_seal(plt,
sealer_pltgot);
else
#endif
obj->pltgot[1] = (uintptr_t)obj;
plt->pltgot[1] = (uintptr_t)plt;
#ifdef CHERI_LIB_C18N
if (C18N_ENABLED)
obj->pltgot[2] = (uintptr_t)&_rtld_bind_start_c18n;
plt->pltgot[2] = (uintptr_t)&_rtld_bind_start_c18n;
else
#endif
obj->pltgot[2] = (uintptr_t)&_rtld_bind_start;
plt->pltgot[2] = (uintptr_t)&_rtld_bind_start;
}
}

Expand Down Expand Up @@ -406,8 +406,9 @@ reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela,
* Process the PLT relocations.
*/
int
reloc_plt(Obj_Entry *obj, int flags, RtldLockState *lockstate)
reloc_plt(Plt_Entry *plt, int flags, RtldLockState *lockstate)
{
Obj_Entry *obj = plt->obj;
const Obj_Entry *defobj;
const Elf_Rela *relalim;
const Elf_Rela *rela;
Expand All @@ -417,13 +418,12 @@ reloc_plt(Obj_Entry *obj, int flags, RtldLockState *lockstate)
#endif
bool lazy;

relalim = (const Elf_Rela *)((const char *)obj->pltrela +
obj->pltrelasize);
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
#ifdef __CHERI_PURE_CAPABILITY__
jump_slot_base = (uintptr_t)cheri_clearperm(obj->text_rodata_cap,
FUNC_PTR_REMOVE_PERMS);
#endif
for (rela = obj->pltrela; rela < relalim; rela++) {
for (rela = plt->rela; rela < relalim; rela++) {
uintptr_t *where, target;
#ifdef __CHERI_PURE_CAPABILITY__
Elf_Addr *fragment;
Expand Down Expand Up @@ -541,19 +541,19 @@ reloc_plt(Obj_Entry *obj, int flags, RtldLockState *lockstate)
* LD_BIND_NOW was set - force relocation for all jump slots
*/
int
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
reloc_jmpslots(Plt_Entry *plt, int flags, RtldLockState *lockstate)
{
Obj_Entry *obj = plt->obj;
const Obj_Entry *defobj;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const Elf_Sym *def;

if (obj->jmpslots_done)
if (plt->jmpslots_done)
return (0);

relalim = (const Elf_Rela *)((const char *)obj->pltrela +
obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
uintptr_t *where, target;

where = (uintptr_t *)(obj->relocbase + rela->r_offset);
Expand Down Expand Up @@ -585,7 +585,7 @@ reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
break;
}
}
obj->jmpslots_done = true;
plt->jmpslots_done = true;

return (0);
}
Expand Down Expand Up @@ -647,28 +647,36 @@ reloc_iresolve_one(Obj_Entry *obj, const Elf_Rela *rela,
*where = target;
}

int
reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
static void
reloc_iresolve_plt(Plt_Entry *plt, struct Struct_RtldLockState *lockstate)
{
const Elf_Rela *relalim;
const Elf_Rela *rela;

if (!obj->irelative)
return (0);
obj->irelative = false;
relalim = (const Elf_Rela *)((const char *)obj->pltrela +
obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
switch (ELF_R_TYPE(rela->r_info)) {
#ifdef __CHERI_PURE_CAPABILITY__
case R_MORELLO_IRELATIVE:
#else
case R_AARCH64_IRELATIVE:
#endif
reloc_iresolve_one(obj, rela, lockstate);
reloc_iresolve_one(plt->obj, rela, lockstate);
break;
}
}
}

int
reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
{
unsigned long i;

if (!obj->irelative)
return (0);
obj->irelative = false;
for (i = 0; i < obj->nplts; i++)
reloc_iresolve_plt(&obj->plts[i], lockstate);
return (0);
}

Expand Down Expand Up @@ -696,20 +704,18 @@ reloc_iresolve_nonplt(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
return (0);
}

int
reloc_gnu_ifunc(Obj_Entry *obj, int flags,
struct Struct_RtldLockState *lockstate)
static bool
reloc_gnu_ifunc_plt(Plt_Entry *plt, int flags, RtldLockState *lockstate)
{
Obj_Entry *obj = plt->obj;
const Elf_Rela *relalim;
const Elf_Rela *rela;
uintptr_t *where, target;
const Elf_Sym *def;
const Obj_Entry *defobj;

if (!obj->gnu_ifunc)
return (0);
relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
where = (uintptr_t *)(obj->relocbase + rela->r_offset);
switch (ELF_R_TYPE(rela->r_info)) {
#ifdef __CHERI_PURE_CAPABILITY__
Expand All @@ -720,7 +726,7 @@ reloc_gnu_ifunc(Obj_Entry *obj, int flags,
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
SYMLOOK_IN_PLT | flags, NULL, lockstate);
if (def == NULL)
return (-1);
return (false);
if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC)
continue;
lock_release(rtld_bind_lock, lockstate);
Expand All @@ -738,6 +744,20 @@ reloc_gnu_ifunc(Obj_Entry *obj, int flags,
(const Elf_Rel *)rela);
}
}
return (true);
}

int
reloc_gnu_ifunc(Obj_Entry *obj, int flags,
struct Struct_RtldLockState *lockstate)
{
unsigned long i;

if (!obj->gnu_ifunc)
return (0);
for (i = 0; i < obj->nplts; i++)
if (!reloc_gnu_ifunc_plt(&obj->plts[i], flags, lockstate))
return (-1);
obj->gnu_ifunc = false;
return (0);
}
Expand Down
2 changes: 2 additions & 0 deletions libexec/rtld-elf/aarch64/rtld_machdep.h
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,8 @@

struct Struct_Obj_Entry;

#define MD_PLT_ENTRY

#define MD_OBJ_ENTRY \
bool variant_pcs : 1; /* Object has a variant pcs function */

Expand Down
2 changes: 1 addition & 1 deletion libexec/rtld-elf/aarch64/rtld_start.S
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -181,7 +181,7 @@ ENTRY(C18N_SYM(_rtld_bind_start))
#endif
add x1, x1, x3 /* reloff = x3 + offset = (3 or 1.5) * offset */

/* Load obj */
/* Load plt */
ldr PTR(0), [PTR(16), #-PTR_WIDTH]

/* Call into rtld */
Expand Down
81 changes: 52 additions & 29 deletions libexec/rtld-elf/amd64/reloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -114,11 +114,11 @@ do_copy_relocations(Obj_Entry *dstobj)

/* Initialize the special GOT entries. */
void
init_pltgot(Obj_Entry *obj)
init_pltgot(Plt_Entry *plt)
{
if (obj->pltgot != NULL) {
obj->pltgot[1] = (Elf_Addr) obj;
obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
if (plt->pltgot != NULL) {
plt->pltgot[1] = (Elf_Addr) plt;
plt->pltgot[2] = (Elf_Addr) &_rtld_bind_start;
}
}

Expand Down Expand Up @@ -326,13 +326,14 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,

/* Process the PLT relocations. */
int
reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused)
reloc_plt(Plt_Entry *plt, int flags __unused, RtldLockState *lockstate __unused)
{
Obj_Entry *obj = plt->obj;
const Elf_Rela *relalim;
const Elf_Rela *rela;

relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
Elf_Addr *where;

switch(ELF_R_TYPE(rela->r_info)) {
Expand All @@ -357,15 +358,16 @@ reloc_plt(Obj_Entry *obj, int flags __unused, RtldLockState *lockstate __unused)

/* Relocate the jump slots in an object. */
int
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
reloc_jmpslots(Plt_Entry *plt, int flags, RtldLockState *lockstate)
{
Obj_Entry *obj = plt->obj;
const Elf_Rela *relalim;
const Elf_Rela *rela;

if (obj->jmpslots_done)
if (plt->jmpslots_done)
return 0;
relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
Elf_Addr *where, target;
const Elf_Sym *def;
const Obj_Entry *defobj;
Expand Down Expand Up @@ -394,7 +396,7 @@ reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
return (-1);
}
}
obj->jmpslots_done = true;
plt->jmpslots_done = true;
return 0;
}

Expand Down Expand Up @@ -427,21 +429,30 @@ reloc_iresolve_one(Obj_Entry *obj, const Elf_Rela *rela,
*where = target;
}

int
reloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate)
static void
reloc_iresolve_plt(Plt_Entry *plt, RtldLockState *lockstate)
{
const Elf_Rela *relalim;
const Elf_Rela *rela;

relalim = (const Elf_Rela *)((const char *)plt->rela +
plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
if (ELF_R_TYPE(rela->r_info) == R_X86_64_IRELATIVE)
reloc_iresolve_one(plt->obj, rela, lockstate);
}
}

int
reloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate)
{
unsigned long i;

if (!obj->irelative)
return (0);
obj->irelative = false;
relalim = (const Elf_Rela *)((const char *)obj->pltrela +
obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
if (ELF_R_TYPE(rela->r_info) == R_X86_64_IRELATIVE)
reloc_iresolve_one(obj, rela, lockstate);
}
for (i = 0; i < obj->nplts; i++)
reloc_iresolve_plt(&obj->plts[i], lockstate);
return (0);
}

Expand All @@ -462,16 +473,15 @@ reloc_iresolve_nonplt(Obj_Entry *obj, RtldLockState *lockstate)
return (0);
}

int
reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
static bool
reloc_gnu_ifunc_plt(Plt_Entry *plt, int flags, RtldLockState *lockstate)
{
Obj_Entry *obj = plt->obj;
const Elf_Rela *relalim;
const Elf_Rela *rela;

if (!obj->gnu_ifunc)
return (0);
relalim = (const Elf_Rela *)((const char *)obj->pltrela + obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
relalim = (const Elf_Rela *)((const char *)plt->rela + plt->relasize);
for (rela = plt->rela; rela < relalim; rela++) {
Elf_Addr *where, target;
const Elf_Sym *def;
const Obj_Entry *defobj;
Expand All @@ -482,7 +492,7 @@ reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
SYMLOOK_IN_PLT | flags, NULL, lockstate);
if (def == NULL)
return (-1);
return (false);
if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC)
continue;
lock_release(rtld_bind_lock, lockstate);
Expand All @@ -492,8 +502,21 @@ reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
break;
}
}
obj->gnu_ifunc = false;
return (0);
return (true);
}

int
reloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
unsigned long i;

if (!obj->gnu_ifunc)
return (0);
for (i = 0; i < obj->nplts; i++)
if (!reloc_gnu_ifunc_plt(&obj->plts[i], flags, lockstate))
return (-1);
obj->gnu_ifunc = false;
return (0);
}

uint32_t cpu_feature, cpu_feature2, cpu_stdext_feature, cpu_stdext_feature2;
Expand Down
2 changes: 2 additions & 0 deletions libexec/rtld-elf/amd64/rtld_machdep.h
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,8 @@

struct Struct_Obj_Entry;

#define MD_PLT_ENTRY

#define MD_OBJ_ENTRY

/* Return the address of the .dynamic section in the dynamic linker. */
Expand Down
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